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387
TECHNICAL SECTION
ENGINE PROBLEMS
POOR HOT STARTS
Corvairs seem to be plagued with 2 types of hot starting problems. 1. Flooding condition
2. Slow turning starting
1. FLOODED – Generally caused by cool gas being pumped into the carburetor and engine being turned off. The gas is heated by engine heat
and expands and floods. The engine turns fast but just doesn't seem to want to start. Eventually starts if you hold your foot
to the floor. About the only cure I have found is to rebuiId the carburetors, set float lower than specifications call for. Be sure
chokes are not setting too much for hot weather.
2. SLOW TURNING ENGINE – This problem seems to be very common. When cold or turned off for 1-2 hours car starts "instantly". Drive it
for 2 or more miles in hot weather and turn off and when you try starting it – it just barely turns for 2-3 turns and
then either gets slower or speeds up. Often just releasing the key and trying again it will start normally. There are
many things you can check for with this problem. We have done EVERYONE of these things and still sometimes
have trouble. Maybe someone knows of something more!
A. Battery must be in perfect condition, especially terminals.
B. Battery cables must be in good condition and clean at both ends (our non-original cables are one size
larger than GM which helps).
C. Be sure generator/alternator and voltage regulator are in good condition.
D. STARTER – Often this condition just indicates your starter needs to be rebuilt (brushes, turn armature,
new solenoid). In some cases if armature has already been turned before you may have to get another
armature. Another problem is the center of the armature being too large and when it warms up it expands
slightly and starts to ground out.
HEAD TEMP SENDER UNITS Will yours FAIL at too low OR too high a temp?
Replace those old units that can give you FALSE READINGS and POSSIBLY RUIN YOUR ENGINE! The small bimetallic strip inside
can FAIL 3 WAYS. Constant heating and cooling can cause them to either get weak so they come on too soon or get brittle and
come on too late. Over the years moisture can also cause corrosion and possibly NO CONTACT
. Even though the originals and our
repros were silver plated, switches that are 10-15 years old CAN EASILY HAVE OVER A 50% FAILURE RATE. See #44, page 20.
OVER HEATING
1. Some people incorrectly think that their Corvair is over heating because of some of the following reasons:
A. It smokes around the engine! This could just be that your seals, gaskets, or o-rings are leaking oil, that is then getting on the
manifolds and turning to whitish blue smoke. Has nothing to do with car running hot.
B. The engine "sounds" hot when I stop. In cold weather, wet weather, or very hot weather you may hear the engine "cracking"
hissing, etc., but usually this is just normal expansion and contraction or water that has just gotten splashed onto the exhaust.
C. It's hot to touch! Most any Corvair engine is "hot to touch" after 1-5 miles depending on the outside temperature. This is a
difficult way to tell.
If a person keeps extremely close watch over his engine then the above may be enough to tell him that it is over heating, otherwise most of
us have to rely on the idiot light (unless you have a heat temperature gauge). The idiot lights can also give you false readings for the following
reasons:
A. The wiring grounds to the engine shrouds where it goes near them.
B. The switch on the right head that "runs" the idiot light goes bad and registers at a lower temperature than it should.
(Don't forget the oil pressure switch runs the same idiot light). Both of these situations can be checked quite cheaply and easily.
ACTUALLY OVER HEATING
Let's say your car is actually over heating. What do you check?
A. Tune-up – If the engine is very poor or you are using very poor gas.
B. Something such as a cleaning towel drawn into the fan shroud?
C. Oil cooler cover not removed and cleaned out.
D. The rear heat outlet doors damaged and can't open from the bellows force?
E. Seals between engine and body missing (especially at the rear) allowing engine to draw back in hot air from the rear.
F. Engine needs rebuild. If engine is in very poor overall condition it can run hotter.
G. Wrong jet in carburetor – try next step richer.
These are just some of the things that can cause over heating.
THERMOSTAT DOORS
The rods should be adjusted such that when the engine is cold the doors are closed with just a slight tension and will open fully to a horizontal position.
MY THERMOSTATS AREN'T WORKING
The 1961-69 Corvairs have 2 thermostats (bellows). The doors close when the engine is cool as this helps it reach optimum operating temperature
sooner. When cool the thermostats contract, when hot they expand. When a thermostat goes bad it stays expanded even when cool. This opens the rear
heat doors so an engine can't over heat. "My doors don't open?" In cool weather it may take 10-15 minutes of idling before the doors will open. Even
after a drive the doors may have closed just before you stop to look at them.
387TECHNICAL SECTIONENGINE PROBLEMSPOOR HOT STARTSCorvairs seem to be plagued with 2 types of hot starting problems. 1. Flooding condition 2. Slow turning starting 1. FLOODED - Generally caused by cool gas being pumped into the carburetor and engine being turned off. The gas is heated by engine heat and expands and floods. The engine turns fast but just doesn't seem to want to start. Eventually starts if you hold your foot to the floor. About the only cure I have found is to rebuiId the carburetors, set float lower than specifications call for. Be sure chokes are not setting too much for hot weather.2. SLOW TURNING ENGINE - This problem seems to be very common. When cold or turned off for 1-2 hours car starts "instantly". Drive it for 2 or more miles in hot weather and turn off and when you try starting it - it just barely turns for 2-3 turns and then either gets slower or speeds up. Often just releasing the key and trying again it will start normally. There are many things you can check for with this problem. We have done EVERYONE of these things and still sometimes have trouble. Maybe someone knows of something more!A. Battery must be in perfect condition, especially terminals.B. Battery cables must be in good condition and clean at both ends (our non-original cables are one size larger than GM which helps).C. Be sure generator/alternator and voltage regulator are in good condition.D. STARTER - Often this condition just indicates your starter needs to be rebuilt (brushes, turn armature, new solenoid). In some cases if armature has already been turned before you may have to get another armature. Another problem is the center of the armature being too large and when it warms up it expands slightly and starts to ground out.HEAD TEMP SENDER UNITS Will yours FAIL at too low OR too high a temp?Replace those old units that can give you FALSE READINGS and POSSIBLY RUIN YOUR ENGINE! The small bimetallic strip inside can FAIL 3 WAYS. Constant heating and cooling can cause them to either get weak so they come on too soon or get brittle and come on too late. Over the years moisture can also cause corrosion and possibly NO CONTACT. Even though the originals and our repros were silver plated, switches that are 10-15 years old CAN EASILY HAVE OVER A 50% FAILURE RATE. See #44, page 20.OVER HEATING1. Some people incorrectly think that their Corvair is over heating because of some of the following reasons: A. It smokes around the engine! This could just be that your seals, gaskets, or o-rings are leaking oil, that is then getting on the manifolds and turning to whitish blue smoke. Has nothing to do with car running hot. B. The engine "sounds" hot when I stop. In cold weather, wet weather, or very hot weather you may hear the engine "cracking" hissing, etc., but usually this is just normal expansion and contraction or water that has just gotten splashed onto the exhaust. C. It's hot to touch! Most any Corvair engine is "hot to touch" after 1-5 miles depending on the outside temperature. This is a difficult way to tell.If a person keeps extremely close watch over his engine then the above may be enough to tell him that it is over heating, otherwise most of us have to rely on the idiot light (unless you have a heat temperature gauge). The idiot lights can also give you false readings for the following reasons: A. The wiring grounds to the engine shrouds where it goes near them. B. The switch on the right head that "runs" the idiot light goes bad and registers at a lower temperature than it should. (Don't forget the oil pressure switch runs the same idiot light). Both of these situations can be checked quite cheaply and easily.ACTUALLY OVER HEATING Let's say your car is actually over heating. What do you check? A. Tune-up - If the engine is very poor or you are using very poor gas. B. Something such as a cleaning towel drawn into the fan shroud? C. Oil cooler cover not removed and cleaned out. D. The rear heat outlet doors damaged and can't open from the bellows force? E. Seals between engine and body missing (especially at the rear) allowing engine to draw back in hot air from the rear. F. Engine needs rebuild. If engine is in very poor overall condition it can run hotter. G. Wrong jet in carburetor - try next step richer. These are just some of the things that can cause over heating.THERMOSTAT DOORSThe rods should be adjusted such that when the engine is cold the doors are closed with just a slight tension and will open fully to a horizontal position.MY THERMOSTATS AREN'T WORKINGThe 1961-69 Corvairs have 2 thermostats (bellows). The doors close when the engine is cool as this helps it reach optimum operating temperature sooner. When cool the thermostats contract, when hot they expand. When a thermostat goes bad it stays expanded even when cool. This opens the rear heat doors so an engine can't over heat. "My doors don't open?" In cool weather it may take 10-15 minutes of idling before the doors will open. Even after a drive the doors may have closed just before you stop to look at them.
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